Automatic tire pressure maintainer



' mgl 0d. 6, 1931. J, w, PQQRMAN 1,826,523

AUTOMATIC TIRE PRESSURE MAINTAINER Filed March 8. 1929 2 Sheets-Sheet l v i2 ."W '76 l ATTORNEY 01.6, 1931. 1w. ORMAN 1,826,523

AUTOMATIC TIRE PRESSURE MAITAINER Filed March 8. 1929 2 Sheets-Sheet 2 J Wij-70010710,

vINVENTOR ATTORNEY Fatentecl @et 6, 1931 unirse srnras Jomr w. roonnnn, or nnarrcnnsrnn, omo

,AUTOMATIC TIRE PRESSURE MAINTAINEB Application led March 8, 1929. Serial No. 345,344.

This invention relates to automatic tire' pressure maintainers and more particularly to an automatic air injecting device that will maintain the tire of an automobile in inflated condition at all times andunder all conditions of travel of the vehicle.

A -still further object of the invention is j to provide a tire inlating device that will be operative to automatically inflate the tire of a vehicle whenever the pressure in the same drops below a predetermined minimum, re-

gardless of whether the lvehicle is at a standstill or whether the same is moving over the surface. It is obviousl then'a device, that will-accomplish these features will eliminate vthe. necessity ofthe operator of the vehicle testing the tires for pressure at frequent intervals and -it will eliminate the. necessity of frequenty Search for a public air hosev and i the subsequent discomfort of having to go through the operation of refilling the tires.

Such a device will further reduce the Apossibility of encountering tire trouble on the road as the tire may be kept inflated'even though the'tire is punctured until it is convenient for the operat'or to have the same repaired,

-With these and many other objects 1n v1ew 7 that will more readily appear as the nature of the invention is better understood, the

same consists inthe novel construction, combinationand arrangement of parts' shown in the accompanying drawings in which Figure 1 s a transverse sectional view taken thru a vehicle wheel, showing the manner in which the principles of my invention are applied tothe front a vehicle wheel. I y y Figure 2 is a diagrammatical view, illustrating the motor and compressor. Figure 3 is an enlarged sectional view taken thru the tire valve shown-in Figure 2. VFigure 4 is a sectional view similar to Figure 1 showing the principles of the inventraction Wheels of l' tion applied to the rear differential traction wheels of the vehicle.

Figure 5 is a sectional view taken along the line 5-5 of Figure 4.

Figure 6 is a sectional view taken along m the line 6*(3 of,Figure 4.

Figure 7 is a fragmentary enlarged sectional view illustrating the electrical connection employed in the hub of the rear wheel.

ln all of the above mentioned views, like characters of reference are employed to designate like parts and the rim of a motor vehicle Wheel is shown at 10. This rim is of the conventional type and is provided with the usual tire retaining flanges 12 adapted to @o maintain the beads 14 of a tire 16 therebetween. The wheel is shown at 18 and this wheel may be of any standard type, as for example either disk, wire, wood or the like but in the Vaccompanying drawings Il have preferred to show the'same as being of the wooden spoke type for convenience of description.

The wheel is provided with spokes 18, secured to a felly 11 having the rim thereon. 70 The inner ends of the spokes are connected to a common hub plate 20 by means of suitable hub bolts 22. A spindle is designated at 24. This spindle is formed integrally with a spider 26, the ends fof which terminate in bushings 28 presenting aligned apertures 30 and-32. The bushings 28 are adapted to receive therebetween a bushing 34 formed on the front axle 36 and having a bore 38 therein in alignment with the apertures 3 0 and 32. 8

A spindle 40 extends thru the bushings 28 and 34 and holds these parts in pivotal relationship.v The hub plate 20 is provided y with a hub casing 42 having the usual grease 85 vchamber 44 therein. The hub casing is provided with inner and outer bearings 46 and 48 respectively in which bearings the spindle 24 is mounted. The above mentioned parte as described are purely conventional in their 00 forml and no claim is made as to the novelty. of the same. A

' The novelty lies inthe arrangement o parts whereby the tire may be automatically inflated, `and which will now be described-in full. A conductor strip 29 is fastened to the elly and the hub to form a part4 of an electrical circuit which will be hereinafter more full described.` The telly 11 "has aligned apertures 50 therethrough throng which a` tire valve casing 52 is a apted to pass.. A pair of retaining nuts 56, threaded onto'the casing, clamp the inner tube 58-` of the tire 16 therebetween. v

Positioned in the casing 52 is a soft rubber member 60 having avbrass plug 62 in the top thereof.. The plug 62 is provided with a tubular shank 64., 'This shank is provided with a nut 65 on its inner end. 'Mounted Within the shank 64. and threadedly held against displacement therein ,is the conventional type of Schrader valve 66 commonly used in automobile tire valve stemsn lThe shank 64, together with the members 60 and 62, are slidable within the casing 52 and the shank is insulated from the side of this casing by a tubular sleeve 68 having a plug 70 threaded therein to provide a recess 72 in which there is disposed a coil spring 73 normally adapted to urge the plug 62 and the shank 64 surrounding the sleeve 60,-'out- Wardly into engagement with a contact 7 4 on -zsol a compressor or the like, the motor yof l`which .a The' pipe 76 isv insular the inside of the-casing 52. vThe inner end o' the casing 52 is threaded interiorly vand is adapted to 4receive the end of a steel pipe 76l having insulation 78 thereon. This pipe .is connected to the shank 64 by a conductor 80 in the form of a coil springo It will be seen, therefore, that the plug 62 and its depending. shaft 64 having the Schrader. valve therein, together with' the pipe 76, is insulated from the valve casing 52 vby means of the insulation 60, 68 and 78, for

a purpose to be described hereinafter.

vIt will also be seen that when the valve assembly is in a position on a vehicle tire at high pressures, the force exerted on the facek of the plu 62 and its surrounding sleeve 60 will be su cient to force the plug away from the contact 7 4,' lbut at low pressures, depending on the tension of the coil spring '73, the plug 62 will be urged into contact'vvith the contact 74. l

v The pipe 76 is bent, as at 81, to extend downwardly into 1the hub cap 42, where the ,same is reversed, as at 84, with itsextremity in communication with a bore 82 extending longitudinally ythrough the spindle 24. The said part 84'fis lconnected with the s indleby a packingy nut. Another section o the.p1pe passes through the spindle and passes therefrom atr86, `andlea'ds .to theexhaust side of is shownlatfM in Figure v1. t l ed throughoutitsl Losetas "of the spring 73 may diagrannnatically shown in Figure -1 and vdesignated c, is connected to this pi e and to one terminal of the motor M. T e other terminal of this motor is electrically connected to a battery B which is connected to a.

hielo, and I will new proceed with a full description of the operation of the device.

' When the tire is fully inlated under norymal conditions, depending upon the weight of the car, size and style of the tire and other contributing factors, the pressure of air in the tire, acting upon the upper surface of the plug 62 inthe rubber bushing 60, will be sufficient to maintain the same out of contact with. the. element 74 so that the circuit through the motorM will be open, thereby rendering the compressor inoperative. However, if the pressure in the tire should drop yloelovsT the predetermined minimum, due to any cause, such as leakage of air or puncture of the tire, determined by `the `tension of the spring 73, the spring will urge the plug 62 into contact with the element 74 andclose the `circuit through the motor M, conductor c, pipe 76, contact 7 4, valve stem 52 and strip 29 to the metal part of the wheel or ground. This will cause the motor M to drive the compresser and supply air through the pipe 76 e entire length from. all metal parts of the wheel or rame'of the vehicle and a conductor,

will

the motor M to stop the same. The tension of the spring 7 3 can be adjusted by means of the plug 70. This occurs when the popv off valve opens thereby relieving the pressure on the inner end of the valve62. The tension be adjusted.` by means of the plug 17. f

Figures 4,5 and 6 show the arrangement of4 parts used on' each rearv wheel. ln this case, amemloery 87 is fastened to the hub of the rear wheel and is formed with an annular part 88 which contains on its vinner face a pair of, annularf'grooves 89 and a. larger annular groove 90`Which is arranged between the grooves 89.? The insulated pipe 76',

communication with the groove 90. /A member 91 is arrangedonthe rear housing 92 and v is formed .vvithganv annular part 93, vvl 1ichv ',abutsthe annularpart 88 and thislpart 91 fleas -onl its outer face the annular.v ribs 94 which enter the grooves 89 and ys ring pressed packing y,n1eans95 are placed 1n the ;v`

nis

grooves 89 and bear upon the ribs 94. This member 91 is also formed with a port 96 to recelve an end of a pipe 97 which is connected with the compressor, and as the port 96 is in communication with the groove 90, air will enter the groove and thusv pass through the pipe 76 to the valve mechanism in the stem 72 and the packing means 95 will prevent escape of air from the groove. The member 91 is pressed against the member 87 through means of the springs 98 on the bolts 99 which connect. the .member 91 with a 'flange 100 on the housing 92. These bolts pass through slots 101l in the member` 91, sol that this member is self-adjusting to the relative movement nected to the motor M. The member 91 carev l ries the brake drum 104.

Thusit will be seen that the arrangement of the members 87 and 91 will permit air to pass from the supply pipe 97 to the pipes 76 while the wheel is rotating, and the shoe electrically connect the member. 87 with the motor of the generator while the wheel is rotating, so that as soon as the member 62 engages the contact 7 4, the circuit to the motor will be completed and the generator started.

The pressure generated by the compressor should be adjusted according to thepressure carried by the tires. For instance, if the tires are to carry .a pressure of 40 pounds, the compressor pressure should be somewhere e between 40 pounds and 45 pounds, so as not to open the valves of the other tubes, thereby adding to their pressure also. A It is thought from the. foregoin description that the advantages and nove features A of the invention will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts, provided that such changes. fall wthln the scopeof the appended claim.

What I clalm isz- A n automatic tire pressure maintainer comprising a casingv one end of which is mounted 1n and in communication with a tire and the4T other end connected to an electrically actuated air supply means, a stationary contact carried by the interior of the casing and electrically connected to said supply means, an insulatlng sleeve-mounted in the casing, a cushion member of insulating material in the casing and engagin one end of the sleeve, a tubular member sli able in said sleeve and cushion member and having a head to abut the cushion member when in one position, said tubular member constituting a iston subject to air pressure in the tire and orming a movable contact and electrically connected to said 4supply means, a valve in said tubular member to admit air under pressure to the, tire and adapted to prevent escape of air from the tire, and tension means for urging the tubular member into engagement with the stationary contact when the air. ressure in the tire actin against the head o? the tubular member alls below a predetermined pressure.

In testimony whereof I aiix my signature.

JOHN W. POORMAN. 

